4 Answers

If you bought this phone in the US, then the default carrier for the iphone4 is AT&T, which might not be available in India. You have to get a compatible SIM from a carrier in India, then see if the phone will even work with their SIM.

HI the message "invalid sim" means that your iphone 4 is locked to network provider in USA due to this it can't be used in India unless you unlock it .If you want to unlock your iphone 4 from network lock .Then visit here they unlock iphone using remote unlocking service .

Invalid sim indicates that your phone is locked to a particular network. You have mentioned that you bought your phone from US. It seems to be your phone is locked with one of the US network. You need to unlock it from your locked network. For that, contact your service provider/contact any of the online vendors like Onlinegsmunlock.com to fix your problem . Once, you have unlocked your phone from sim lock successfully, you can easily switch over from your network to other GSM networks.